Automatic fastening device with bolts for concrete molds

ABSTRACT

A device capable of tightening or loosening the fastener bolts on a concrete mold successively in an automatic fashion without necessitating intermittent feed of the mold. A bolt driver unit is mounted on a manipulator and is positioned for bolt tightening or loosening operation only when a fastener bolt is detected upstreamside of the manipulator but is retracted whenever any rib, tire or other radial projection on the mold is detected. For detection, an appropriate object recognition system is usable which utilizes image information taken by an industrial television camera. The device can serve molds practically of every make owing to its construction and mode of operation.

United States Patent Tokunaga et al. June 3, 1975 [54] AUTOMATICFASTENING DEVICE WITH 3,265,130 8/1966 Watkins 166/.6

BOLTS FOR CONCRETE MOLDS [75] Inventors: Takeshi Tokunaga; ToshiakiPrimar y ExammerJames L. Jones, Jr. Maekawa, both of l-litachl; TakeshlUno Tokyo; Tadashi g Attorney, Agent, or Fzrm Oldham & Oldham Co.Shimodate; Nobuyuki Abe, Shimodate; Takeo Kume, Shimodate; Yukio OhnishiShimodate; Yasumi Shimoinura, [57] ABSTRACT Tokyo, all of Japan A devicecapable of tightening or loosening the fas- [73] Asslgnee' E'P g l KogyoKabushlkl tener bolts on a concrete mold successively in an autoals 0apan matic fashion without necessitating intermittent feed [22] Filed:July 19, 1974 of the mold. A bolt driver unit is mounted on amanipulator and is positioned for bolt tightening or loosen- [211 App]'490085 ing operation only when a fastener bolt is detected upstreamsideof the manipulator but is retracted when- [52] U.S. Cl 81/54; 166/.6 v rny ri ir r her radial projection on the [51] Int. Cl B25b 13/00; B25b21/00 m ld i detected For detection, an pp pr at j t [58] Field ofSearch 81/54, 57.37; 166/.6; recognition system is usable which utilizesimage in- 173/ 1; 175/7 formation taken by an industrial televisioncamera. The device can serve molds practically of every make [56]References Cited owing to its construction and mode of operation.

UNITED STATES PATENTS 2,981,347 4/1961 Bauer et al. 175/7 1 Claim, 12Drawing Figures PATENTEDJUH 3 I975 SHEET .lll llihhn ll AUTOMATICFASTENING DEVICE WITH BOLTS FOR CONCRETE MOLDS BACKGROUND OF THEINVENTION This invention relates to the bolt fastening of concrete moldsor formworks of the-type used in forming concrete piles or the likeconcrete products and is intended to provide a device which is operableautomatically to tighten or loosen the fastener bolts on such concretemolds.

The bolt-fastening operation must be carried out under various workconditions. Among others, there are a wide variety of molds to beserved, which differ from each other in size and configuration; and nointermittent feed is allowed for the work because of the high note ofproduction required. Fastener bolts are usually arranged on the mold atirregular intervals. Molds of the type described not only includemembers such as ribs and tires, which extend radially outward beyond thefastener bolts, but are tapered with opposite end diameters differingfrom each other.

Under these conditions, it has previously been very difficult tomechanize the bolt driving operation to any substantial extent and, inactual practice, the operator has been required to stand in anappropriate position along the line of mold flow and work manually totighten or loosen the fastener bolts on the mold, keeping time with theadvancing movement thereof. In addition, so-called impact wrenchesnormally used in such operation are of considerable weight, rendering itvery hard for the operator to work continuously for any extended periodof time.

SUMMARY OF THE INVENTION Under these circumstances, the presentinvention has its object the provision of an automatic bolt-fasteningdevice for concrete molds of the type described which in performancestands comparison favorably with human labor.

Another object of the present invention is to provide a device of thecharacter described which includes a detecting section designed todetect the configuration and position of the concrete mold with itsdifferent components and a working section or manipulator carrying abolt driver unit operable to tighten or loosen the fastenerbolts on themold in travel.

Other objects and advantages of the present invention will be apparentfrom the following description when taken in conjunction with theaccompanying drawings, which illustrate one preferred embodiment of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a perspective view illustrating the general arrangement of amold for forming concrete piles and a bolt-fastening device embodyingthe principles of the present invention;

FIG. 2 is a block diagram illustrating the electric control circuitry ofthe bolt-fastening device;

FIG. 3 is a side view, partly in section, of the bolt driver supportingstructure of the device shown in FIG.

FIG. 3a is a cross-sectional view taken substantially along the lineIlla Illa in FIG. 3;

FIG. 4 is a perspective view of the detecting section of thebolt-fastening device;

FIGS. 5 and 5a diagrammatically illustrate respective television imagessuccessively taken of a bolt sustainer block;

FIG. 6 is an explanatory diagram of an imagerecognizing frame formation;

FIG. 7 illustrates the overlapping relationship of a block image withthe image recognizing frame, shown in FIG. 6;

FIGS. 7a and 7b are diagrams explaining the principle of imagerecognition and showing the manner in which respective calculationsindicated vary with the position of the block image relative to therecognizing frame; and

FIG. 8 is a circuit diagram of the image processing system.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings andfirst to FIG. 1, reference numeral 1 generally indicates a pile mold,which is moved in a direction indicated by the arrow by means of acarriage, not shown. The mold 1 has fastener bolts 2 arranged on itsside to be tightened or loosened, and carries ribs and tires, both shownonly one, as indicated at 3 and 4, respectively, and which extendradially outward from the mold body usually to form a trouble inoperation, the tires 4 being generally larger than ribs 3 in radialextent.

The ribs 3 have respective external diameters varying gradually withtheir axial location on the mold I, which is tapered, while tires 4 haveall the same external diameter irrespective of the mold taper. As shown,the faster bolts 2 are each mounted on the mold side by means of a boltsustainer block 13 so that they may not tilt or fall off the mold.

For bolt fastening or unfastening operation, various work conditionsmust be taken into account as pointed out before. First, the bolts 2,ribs 3 and tires 4 are not only irregular in order of arrangement on themold but are arranged, respectively, at irregular intervals axially ofthe mold. Further, molds flowing along one and the same line ofoperation are usually not of the same configuration, differing one fromanother in external diameter, axial length and in spacing and order ofwork members. In addition, such molds are required to be fedcontinuously but not in any intermittent fashion be cause of the hightact of operation required and substantial mold weight.

Under these conditions, the working section of the bolt-fasteningdevice, which takes the form of a manipulator 12 in the embodimentshown, is required to be synchronized with movement of the mold 1 forbolt tightening or loosening operation and includes a bolt driver unitarranged so as to be retracted clear of any approaching rib 3 or tire 4.

Further, the detecting section of the bolt-fastening device is requiredto be of a versatile non-contacting type which is capable of detectingbolts 2, ribs 3 and tires 4 at all times without fail irrespective oftheir irregularities in spacing or order and need not be retracted inany manner as to clear the ribs and tires.

Accordingly, the present invention employs an object recognizing devicefor detection of bolts 2 and ribs 3, which utilizes an industrialtelevision camera 9 as an input means. For detection of tires 4,however, the device of the present invention employs an appropriate tiredector 10, for example, in the form of a microswitch as the televisioncamera 9 can hardly be focused for tires 4, which have all the sameexternal diameter irrespective of the mold taper and a radial extentmuch larger than that of ribs 3 and bolts 2 particularly at locationsclose to the smaller diameter end of mold 1.

Further, the embodiment. illustrated includes a side detector 8 whichserves to set the respective detector units for bolts 2, ribs 3 andtires 4 at a predetermined distance from the mold side each time a mold1 is fed to work station as molds may differ from each other in externaldiameter. As will be understood, the detector units once set are movedforward or backward with respect to'the mold 1 according to the taperthereof.

Operation of the device of the present invention will next be describedtogether with the details of construction and arrangement of the device.

First, when a mold 1 being moved axially in a continuous fashion reachesthe station where the device of the invention is installed, a detector6, for example, in the form of a photoelectric tube or a microswitch,operates to move the side detector 8 a definite distance toward theadjacent side of the mold 1 by the aid of an associated ON-OFF cylinder7. On the other hand, a shaft S, carrying cylinder 7, television camera9, and tire detector 10 in the form of a microswitch, is driven forwarduntil the side detector 8 is brought into contact with the adjacent sideof the mold 1, when the S-shaft comes to stop. In this manner, thetelevision camera 9 and tire detector 10, together forming the detectingsection of the present device, are finally positioned and then the sidedetector 8 alone is retracted under the action of cylinder 7.

The position of the detector section relative to the mold issubsequently corrected by advancing or retracting the S-shaft withrespect to the tapered mold 1 according to the amount of its axialmovement as determined by a pulse generator mounted on the moldcarriage. In this manner, the detecting section can be held at apredetermined distance from the adjacent side of mold 1 irrespective ofthe axial displacement of the latter.

Next, a visual image processor device used to detect bolts 2 and ribs 3will be described with reference to FIGS. 5 et seq.

In this embodiment, bolt sustainer block 13 is employed as an object tobe recognized for detection of the bolt 2 and, when the block 13, movingin the direction indicated by the arrow in FIG. 1, is caught by thetelevision camera 9, it forms an image such as shown in FIG. 5 at acertain instant and subsequently as shown in FIG. 5a. In these figures,the hatched area represents the dark region of the television picture,the remaining area representing the light region thereof. As willreadily be understood, such television picture can be obtained by givingdifferent brightnesses or colors to the object of recognition, i.e., thebolt sustainer block 13, and its background. For recognition of suchimage input, a row of four closely adjourning regions A, B, C and D aredefined within the area of image frame, as shown in FIG. 6. Regions Aand D at the opposite ends and intermediate regions B and C,respectively, have the same horizontal width and the sum of thehorizontal widths of the intermediate regions B and C is equal to thehorizontal width of the image of bolt sustainer block 13. With endregions A and D, the image value therein determines the areacorresponding to the dark background while, with intermediate regions Band C,

It is to be noted that, when the image of bolt sustainer block 13 liesexactly on the regions B and C in combi nation, both S and P become zero(S O, P 0), and that, when the image of block 13 lies slightly to theright, S and P are positive and negative, respectively, that is, S 0 andP 0. Oppositely, when the image of block 13 lies slightly to the left, Sand P are both positive, that is, S 0 and P 0.

Such relationship between the position of the image of block 13 and thevalues of S and P will be readily understood from FIGS. 7, 7a and 7b.FIG. 7 illustrates the position of the image of block 13 relative to therow of regions A, B, C and D at an instant when the horizontally medialpoint or center of the image lies at the point indicated by the blockdot. FIGS. 7a and 7b respectively illustrate the manner in which S and Pvary with movement of the image center along the row of regions A, B, Cand D.

Now it is assumed that the recognition output is to be produced at theinstant when the image of bolt sustainer block 13 passes across theboundary between the intermediate regions B and C, that is, at theinstant when P changes in sign from negative to positive.

However, where an image input is obtained through a television camera asin this case, such image input is obtained once in each field period.Because of this, the image of block 13 effects intermittent motion andhence P cannot attain a value of zero. In addition, S may not be reducedto zero as the bolt sustainer block 13 does'not always produce an imagehaving a horizontal width that is equal to the sum of the horizontalwidths of intermediate regions B and C.

In order to meet these conditions, the image processing system is soarranged as to produce a recognition output at the instant when P hasincreased to zero or further to a positive value as long as S lies belowan appropriate predetermined level.

In FIG. 8, which illustrates the circuit arrangement of the imageprocessing system, reference numeral 36 indicates a circuit for changingthe image input signal from the television camera 9 into binary form;and 37 indicates a sampling circuit provided to horizontally dispersethe binary image input from the circuit 36, which is continuous in time.

Reference numerals 39, 40, 41 and 42 indicate gate circuits forrespective regions A, B, C and D, and 38 indicates a gate signalgenerator giving a gate signal to the gate circuits 39, 40, 41 and 42through respective terminals A, B, C and D. As will readily beunderstood, the gate signal can be easily obtained by utilizing thetiming signal for horizontal sampling and the horizontal synchronizingsignal of television camera 9.

Reference numerals 43 and 44 indicate OR circuits receiving inputs fromgate circuits 39, 40 and from gate circuits 41, 42, respectively; 45indicates another OR circuit receiving inputs from the OR circuits 43and 44; 46 indicates a counter for counting the number of output pulsesof the OR circuit 45; and 47 indicates an updown counter for addition ofthe output of gate circuit 43 and subtraction of that of gate circuit44. Assuming that these counters 46,47 are reset at the start ofscanning, it is to be understood that the outputs of counters 46, 47represent S =a b c'+=d and P a b c d, respectively, at the end ofscanning.

Reference numeral 48 indicates a digital comparator designed to producean output I when the count number of counter 46 is within apredetermined range; and 49 indicates a register for storing the sign ofup-down counter 47 in the preceding image scanning. Reference numeral 50indicates a judgment circuit producing an output only when the output ofregister 49 is negative and the outputs of up-down counter 47 anddigital comparator 48 are zero or positive and 1, respectively. It isarranged so that the output of up-down counter 47 is stored in theregister 49 after the operation of judgment circuit 50 has beencompleted. I

In the manner described above, a timing output can be obtained withrespect to a passing object and, in this case, the output represents arecognition of a bolt sustainer block 13 as imaged in FIG. 5 or 5a. Suchrecognition output is fed to the manipulator control each time a bolt 2flows in. As will readily be understood, ribs 3 can be 'recognized inthe same manner by the provision of another set of circuits 38 et seqwith appropriate settings therefor.

Further, it is to'be understood that the detector is so arranged that anappropriate recognition output is produced and fed to the manipulatorcontrol each time a tire 4 flows in. I V

The manipulator control is so designed that, upon receiving any of suchdetector signals, it converts the detector signal into a positionalinformation and stores such information together with the kind of thework detected in an associated memory. The positional information ischanged according to the movement of mold l and remains stored until theoperation required for the work (that is, tightening or loosening ofbolt 2 or retraction for ribs 3 or tire 4) is completed. Circuitarrangement of the memory is illustrated in FIG. 2.

Referring to FIG. 2, when a detector signal 5 corresponding to a workmember such as bolt 2, rib 3 or tire 4, is received, the output S ofcounter 26, which is counting the number of output pulses S from thepulse generator mounted on the mold carriage, is read into a first-infirst-out type shift register 27 together with the kind of the workmember detected. Subsequentry, the work member enters the range ofmovement of manipulator 12 and, when the latter has completed itsoperation as previously read in, that information is shifted to the laststage register under the direction 5;, from sequence circuit 32. Then,work signal S, is put into the sequence circuit 32 and, in case the workis a bolt 2, the difference between the output S of counter 26 and thepositional information S from the register is calculated in thesubtraction circuit 28 under a preset direction S and the result is readinto the preset counter 29. In this case, however, as the value of theoutput S of preset counter 29, which corresponds to the distance betweenthe work and the detector therefor, must vary with movement of the work,the gate circuit 30 is operated while following its movement by feedingback the position signal S of the manipulator 12 to the servo controltherefor. It is to be understood that the signal S represents thedistance of manipulator 12 from the detecting section.

Referring again to FIG. 1, the manipulator 12 forming the workingsection of the device illustrated includes a shaft T extending in thesame direction as that in which mold l proceeds, another shaft Hextending horizontally at right angles to the direction in which molds lproceeds, and a further shaft V carrying a bolt driver unit 18 to servethe purpose of raising and lowering the unit 18.

Both T and V shafts are required to be able to stop at any positiondesired and are each formed as a servo shaft that obtains feedbackposition information from a pulse generator, resolver or the likedevice. The construction of the V shaft and bolt driver unit 18 willnext be described with reference to FIGS. 3 and 3a.

The bolt driver unit 18, adapted to be raised and lowered by the Vshaft, should be held for operation in a position exactly aligned withthe bolt 2 but, since it is impossible in practice to obtain perfectalignment therebetween, it must be so designed as to accommodate acertain range of misalignment, accordingly, in thedesign shown in FIG.3a, the driver unit 18 is supported by a structure including two pairsof support rails 23 and 24 which extend at right angles to each other toallow the driver unit to move sidewise in either direction for smoothsliding engagement with the bolt 2.

Referring again to FIG. 1, reference numeral 16 indicates a feeler unitprovided beneath the forward end of the H shaft for exact positioning ofthe manipulator relative to the bolt 2. As shown in FIG. 4, the feelerunit 16 is composed of two operating elements 19, 20 and two detectorstaking the form of microswitches 21, 22, and is arranged so that, as itcomes close to the bolt 2, the operating elements 19, 21 are broughtslowly into contact with the bolt, causing operation of detectors 21, 22to complete the positioning of the driver unit 18.

Description will next be made of operation of the manipulator 12.

Assuming that the manipulator 12 is located midway of the T shaft, asshown in FIG. 1, it is started to move at high speed toward the bolt 2as soon as the latter enters the range of movement of the T shaft.Subsequently, when the manipulator 12 has come close to the bolt 2, theT shaft is synchronized with the moving mold 1 on the ON-OFF cylinder15, secured to the H shaft, is actuated to extend the feeler unit 16forward while on the other hand the H shaft is driven forward by theservo cylinder 14. As the result, the feeler 16 is brought intocontacting engagement with the bolt sustainer block 13 and theI-I-direction 22 is actuated causing the T and H shafts to stop.

In order to stop the T shaft, the gate 30 is closed under the follow-updirection S shown in FIG. 2. Subsequently, the T-direction detector 21of the feeler unit 16 is operated with continued movement of the mold 1.Incidentally, if the relative speed between the T shaft and mold 1 istoo high, the pulse signal 8, may conveniently be demultiplied duringthat period for input to the preset counter 29; and, if the relativespeed is too low, the counter 29 may conveniently be 'formed as anup-down counter and be downed.

In this manner, the manipulator 12 is finally and accurately positionedrelative to the bolt 2 and the T shaft again starts to move insynchronism with the movement of mold 1. Simultaneously, the V shaft iscaused to de scend, enabling the bolt driver unit 18 to tighten orloosen the bolt 2, as the case may be, and is raised after driveroperation has been completed.

In this connection, the cylinder 15 is actuated to retract the feelerunit 16 immediately after the positioning has been completed in order tokeep the feeler 16 free from any mechanical vibration during the bolttightening or loosening operation.

Upon completion of such bolt tightening or loosening operataion, a shiftdirection such as indicated at in FIG. 2 is produced to read out thenext stored information and the H shaft is retracted according to thatinformation. That is to say, the H shaft is retracted a little if theread-out information is of a bolt 2; slightly more if it is of a rib 3;and further more if it is of a tire 4. Also, in this case, the T shaftis synchronized with the movement of mold 1 to keep the bolt driver unit18 clear of the rib 3 or tire 4 during the retracting movement of the Hshaft.

Such changing in amount of retraction of the H shaft makes it possibleto increase the tact of operation to a substantial extent. However, incases where the next work is a rib 3 or a tire 4, shift direction S isagain issued upon completion of the retracting movement of H shaft inorder to read out the succeeding stored information.

The above-described sequential operation is effected by input of thekind of work S (FIG. 2) and respective step signals S into the sequencecircuit 32, as indicated in FIG. 2. Only, any detailed explanation ofthe circuit construction of the circuit 32 is believed to be unnecessaryas it can be realized by ROM or other known technique.

It will be appreciated from the foregoing that according to the presentinvention the bolt tightening and loosening operation on molds forforming concrete piles or the like can be fully mechanized and anautomatic bolt fastening device has been provided which has, amongothers, the following advantages:

1. It has realized automatic bolt driving operation for fastener boltson molds for concrete piles or the like for the first time in the art.

2. It can tighten or loosen the fastener bolts on the mold successivelywithout necessitating any interruption in movement of the mold.

3. It is relatively simple in construction just with a simpleapplication of a television camera for recognition of moving objects.

Numerous alterations of the structure herein disclosed will suggestthemselves to those skilled in the art and all such modifications whichdo not depart from the spirit of the invention are intended to beincluded within the scope of the appended claim.

What is claimed is:

1. An automatic bolt-fastening device for molds for forming concretepiles or the like, comprising a manipulator arranged for movementrelative to the mold and carrying a bolt driver unit operable to tightenor loosen the fastener bolts on the mold, detector means arrangedupstream of said manipulator with respect to the movement of the moldrelative thereto to detect the fastener bolts and radially projectingmembers of the mold with the aid of an image information taken by anindustrial television camera, feeler means arranged on said manipulatorfor feeling engagement with the fastener bolt detected, the arrangementbeing such that said bolt driver unit is accurately positioned for bolttightening or loosening operation only when a fastener bolt is detectedby said detector means and is moved into a position clearing any of theradially projecting members of the mold when such member is detected.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,886,821 Dated June 3, 1975 Inventor(s) Take shi Tokunaga et a1 It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

. Column 6, line 51, change mold l on to mold l and Colum'n 6, line 55,change "H-direction 22" to -H-direction detector o Signed and Scaledthis seventh Day of 0650M 1975 [SEAL] Arrest:

RUTH C. M A 'SON C. MARSHALL DANN AIIFSIHIg ()jjzcer CommissionerofPaIents and Trademarks ORM PC4050 (10- 9) USCOMM-DC 6O376-P59 US.GOVERNMENT PRINTING OFFICE: 1569 0-366-33L

1. An automatic bolt-fastening device for molds for forming concretepiles or the like, comprising a manipulator arranged for movementrelative to the mold and carrying a bolt driver unit operable to tightenor loosen the fastener bolts on the mold, detector means arrangedupstream of said manipulator with respect to the movement of the moldrelative thereto to detect the fastener bolts and radially projectingmembers of the mold with the aid of an image information taken by anindustrial television camera, feeler means arranged on said manipulatorfor feeling engagement with the fastener bolt detected, the arrangementbeing such that said bolt driver unit is accurately positioned for bolttightening or loosening operation only when a fastener bolt is detectedby said detector means and is moved into a position clearing any of theradially projecting members of the mold when such member is detected.